Improvement in burglar-alarms



W. J'. DECKER.

BURGLAR ALARM.

Patented May 22,1877.

. WASHINGTON, D C.

N. PETERS, PHOTO ETTED STATES WILLIAM J. DECKER,

PATENT OFFICE OF NEW YORK, N. Y.

IMPROVEMENT IN BURGLAR-ALARMS.

Specification forming part of Letters Patent N o. I90,96l. dated May 22, 1877; application filed April 20, 1877.

To all whom it may concern Be it known that I, WILLIAM J. DECKER, of the city of N ew York, county of New York, and State of New York, have invented an Improved Burglar-Alarm, of which the following is a specification:

Figure l is a perspective view of my improved burglar-alarm. Fig. 2 is a front view thereof, after the face-plate is removed. Fig. 3 is a top view of the same; Fig. 4, a detail perspective view ofthe paper cap used thereon; Fig. 5, a detail perspective view of the nipple which holds th-e paper cap.

Similar letters ot reference indicate corresponding parts in all the figures.

This invention has for its object the construction of a simple alarm, which can be readily attached to doors or Windows to explode a cap whenever the same are opened, and which is adapted to be used with dat paper caps.

The invention consists in the new combination of parts that constitute the alarm mech anism, and in the use of a conical nipple, made with a dat face, for securing the paper cap in place, all as is hereinafter more fully pointed out.

ln the drawing, the letter A represents the case or shell of the improvedburglar-alarm, made of metal or other fit material. B isa lever pivoted within said shell, and provided at its outer end with a projecting arm, a, which constitutes the hammer of the alarm. A spring, b, bears against the lever B, and has the tendency to throw the hammer a against y the nipple d, that projects rigidly from one side ofthe case A. This nipple is, by preference, a solid piece of nearly conical shape, but flat at that face which is exposed to the hammer, as clearly indicated in Figs. l and 3. U is a catch, pivoted at c to the lever B and adapted to hook over a ledge or rim, f, of the case A, as in Fig. l. When so hooked the lever B is held away from the nipple, and the alarm is set. D is the paper cap. It is ofthe ordinary style, being a flat piece of paper, in whicll the fulminate is held. This cap I providewith a slit, g, as in Fig 4, and through this slit is introduced the nipple d, so that thus the cap is properly held to the nipple. In applying the cap, that part of it which contains the fulminate is placed against the dat face of the nipple, as indicated in Figs. 1 and 5.

The alarm may, by a screw, h, or other means, be fastened to a door-frame, close to the inner edge thereof, so that the free end of the catch C, when it is hooked over the ledge f, will be in the way of the door, as indicated in Fig.1. The door heilig opened will push the catcholf the ledge, and cause the spring to violently force the hammer a against the cap, which is interposed between such hammer and the nipple.

The invention is also applicable to be used on window-slashes, especially by fastening the alarm to the lower rail of the upper sash, so that the free end of the catch C will overhang the lower sash.

Although specially adapted for use on a paper cap, the invention may also be used in connection with other styles of percussion-caps, the shape of the nipple being varied in accordance with the style of cap to be used.

I claim as my invention-l l. In a burglar-alarm, the combination of the shell A, having nipple d and ledge f, with the lever B which carries the hammer a and pivoted catch C, and with the spring b, all arranged to operate substantially as herein shown and described.

2. The conical nipple d, made with a dat face, to be used in connection with a paper cap, substantially as specified.

WILLIAM J. DECKER.

Witnesses:

ERNEST C. WEBB, F. v. BmEsEN. 

